package com.heima.schedule.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.StrUtil;
import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.heima.common.constants.ScheduleConstants;
import com.heima.common.redis.CacheService;
import com.heima.model.schedule.dtos.Task;
import com.heima.model.schedule.pojos.Taskinfo;
import com.heima.model.schedule.pojos.TaskinfoLogs;
import com.heima.schedule.mapper.TaskinfoLogsMapper;
import com.heima.schedule.mapper.TaskinfoMapper;
import com.heima.schedule.service.TaskService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.util.Calendar;
import java.util.Date;
import java.util.List;
import java.util.Set;

@Service
@Transactional
@Slf4j
public class TaskServiceImpl implements TaskService {
    /**
     * 添加延时任务
     * @param task
     * @return
     */
    @Override
    public long addTask(Task task) {
        // 1. 添加任务到数据库中
        boolean success = addTaskToDb(task);
        // 2. 添加任务到Redis中
        if (success){
            addTaskToCache(task);
        }

        return task.getTaskId();
    }


    @Autowired
    private CacheService cacheService;

    /**
     * 把任务添加到Redis中
     * @param task
     */
    private void addTaskToCache(Task task) {
        String key = task.getTaskType() + "_" + task.getPriority();
        // 获取五分钟之后的时间
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MINUTE,5);
        long nextScheduleTime = calendar.getTimeInMillis();

        // 2.1 如果任务的执行时间小于等于当前时间，存入list
        if (task.getExecuteTime() <= System.currentTimeMillis()){
            cacheService.lLeftPush(ScheduleConstants.TOPIC + key, JSON.toJSONString(task));
        } else if (task.getExecuteTime() <= nextScheduleTime) {
            // 2.2 如果任务的执行时间大于当前时间 && 小于等于预设时间（未来五分钟），存入zset中
            cacheService.zAdd(ScheduleConstants.FUTURE + key, JSON.toJSONString(task), task.getExecuteTime());
        }

    }

    @Autowired
    private TaskinfoMapper taskinfoMapper;

    @Autowired
    private TaskinfoLogsMapper taskinfoLogsMapper;

    /**
     * 添加任务到数据库
     * @param task
     * @return
     */
    private boolean addTaskToDb(Task task) {
        boolean flag = false;
        try {
            // 保存任务表
            Taskinfo taskinfo = BeanUtil.copyProperties(task, Taskinfo.class);
            taskinfo.setExecuteTime(new Date(task.getExecuteTime()));
            taskinfoMapper.insert(taskinfo);

            //设置taskId
            task.setTaskId(taskinfo.getTaskId());

            // 保存任务日志数据
            TaskinfoLogs taskinfoLogs = BeanUtil.copyProperties(taskinfo, TaskinfoLogs.class);
            taskinfoLogs.setVersion(1);
            taskinfoLogs.setStatus(ScheduleConstants.SCHEDULED);
            taskinfoLogsMapper.insert(taskinfoLogs);

            flag = true;
        }catch (Exception e){
            e.printStackTrace();
        }

        return flag;
    }

    @Override
    public boolean cancelTask(long taskId) {
        boolean flag = false;
        // 删除任务
        Task task = updateDb(taskId, ScheduleConstants.CANCELLED);
        // 更新任务日志
        if (task != null){
            removeTaskFromCache(task);
            flag = true;
        }
        return flag;
    }

    @Override
    public Task poll(int type, int priority) {

        Task task = null;

        try{
            String key = type + "_" + priority;

            // 从Redis中拉取数据 pop
            String task_json = cacheService.lRightPop(ScheduleConstants.TOPIC + key);
            if (StrUtil.isNotBlank(task_json)){
                task = JSON.parseObject(task_json, Task.class);

                // 修改数据库信息
                updateDb(task.getTaskId(),ScheduleConstants.EXECUTED);
            }
        } catch (Exception e){
            e.printStackTrace();
            log.error("poll task exception");
        }
        return task;
    }

    private void removeTaskFromCache(Task task) {
        String key = task.getTaskType() + "_" + task.getPriority();
        if (task.getExecuteTime() <= System.currentTimeMillis()){
            cacheService.lRemove(ScheduleConstants.TOPIC + key,0,JSON.toJSONString(task));
        }else {
            cacheService.zRemove(ScheduleConstants.FUTURE + key,JSON.toJSONString(task));
        }
    }

    /**
     * 删除任务，更新任务日志
     * @param taskId
     * @param status
     * @return
     */
    private Task updateDb(long taskId, int status) {
        Task task = null;
        try {
            // 删除任务
            taskinfoMapper.deleteById(taskId);

            // 跟新任务日志
            TaskinfoLogs taskinfoLogs = taskinfoLogsMapper.selectById(taskId);
            taskinfoLogs.setStatus(status);
            taskinfoLogsMapper.updateById(taskinfoLogs);

            task = BeanUtil.copyProperties(taskinfoLogs, Task.class);
            task.setExecuteTime(taskinfoLogs.getExecuteTime().getTime());
        }catch (Exception e){
            log.error("task cancel exception taskId = {}",taskId);
        }

        return task;
    }

    /**
     * 未来数据定时刷新
     */
    @Scheduled(cron = "0 */1 * * * ?")
    public void refresh(){

        String token = cacheService.tryLock("FUTURE_TASK_SYNC", 1000 * 30);

        if (StrUtil.isNotBlank(token)){
            log.info("未来数据定时刷新--定时任务");

            // 获取所有未来数据的集合keys
            Set<String> futureKeys = cacheService.scan(ScheduleConstants.FUTURE + "*");


            for (String futureKey : futureKeys) {

                // 获取当前数据的key topic
                String topicKey = ScheduleConstants.TOPIC + futureKey.split(ScheduleConstants.FUTURE)[1];

                //按照keys和分值查询符合条件的数据
                Set<String> tasks = cacheService.zRangeByScore(futureKey, 0, System.currentTimeMillis());

                // 同步数据
                if (!tasks.isEmpty()){
                    cacheService.refreshWithPipeline(futureKey,topicKey,tasks);
                    log.info("成功将"+futureKey+"刷新到了"+topicKey);
                }
            }
        }

    }

    /**
     * 数据库任务定时同步到redis中
     */
    @PostConstruct
    @Scheduled(cron = "0 */5 * * * ?")
    public void reloadData(){

        // 清理缓存中的数据 list zset
        clearCache();
        // 查询符合条件的任务 小于未来5分钟的数据
        // 获取五分钟之后的时间
        Calendar calendar = Calendar.getInstance();
        calendar.add(Calendar.MINUTE,5);
        List<Taskinfo> taskinfoList = taskinfoMapper.selectList(new LambdaQueryWrapper<Taskinfo>().lt(Taskinfo::getExecuteTime, calendar.getTime()));

        // 把任务添加到Redis
        if(taskinfoList != null && !taskinfoList.isEmpty()){
            for (Taskinfo taskinfo : taskinfoList) {
                Task task = BeanUtil.copyProperties(taskinfo, Task.class);
                task.setExecuteTime(taskinfo.getExecuteTime().getTime());
                addTaskToCache(task);
            }
        }
        log.info("数据库中任务同步到了Redis");
    }

    /**
     * 清理缓存中的数据
     */
    private void clearCache() {
        Set<String> topicKeys = cacheService.scan(ScheduleConstants.TOPIC + "*");
        Set<String> futureKeys = cacheService.scan(ScheduleConstants.FUTURE + "*");
        cacheService.delete(topicKeys);
        cacheService.delete(futureKeys);
    }
}
